Wireless apparatus and method for de-masking a packet

Abstract

A wireless apparatus and a method thereof are provided. The wireless apparatus comprises a receiving unit and a processing unit. The receiving unit is configured for receiving a packet which comprises a data portion and a cyclic redundancy check portion from the base station. The processing unit connected to the receiving unit which is configured for generating a de-masked packet by de-masking the cyclic redundancy check portion and at least one selected bit of the data portion by a plurality of predetermined bits, determining that the de-masked packet pass a cyclic redundancy check, and accepting the packet after the determination.

What is claimed is: 
     
       1. A method for de-masking a packet, the method being used in a wireless apparatus of a network system, the network system comprising a base station and the wireless apparatus, the method comprising the steps of:
 receiving, by the wireless apparatus, the packet from the base station, the packet comprising a data portion and a cyclic redundancy check portion; 
 generating, by the wireless apparatus, a de-masked packet by de-masking the cyclic redundancy check portion and at least one selected bit of the data portion by a plurality of predetermined bits; 
 determining, by the wireless apparatus, that the de-masked packet passes a cyclic redundancy check; and 
 accepting, by the wireless apparatus, the packet; 
 wherein the data portion has at least one selected position for placing the at least one selected bit, the at least one selected position corresponds to a plurality of possible bit streams, a first vector space is formed by a plurality of redundancies by applying a cyclic redundancy check polynomial to each of the possible bit streams, a second vector space is further formed by a plurality of redundancies by applying the CRC polynomial to each of all possible bit streams in the CRC portion, and the first vector space and the second vector space do not overlap. 
 
     
     
       2. The method of  claim 1 , wherein the cyclic redundancy check portion is defined with a station identification masked field, the station identification masked field comprises a plurality of bits, and the method de-masks the bits in the station identification masked field by a station identification of the wireless apparatus and de-masks the at least one selected bit in the data portion by an extended-station identification of the wireless apparatus. 
     
     
       3. The method of  claim 1 , wherein the cyclic redundancy check portion is defined with a station identification masked field and a non-station identification masked field, the station identification masked field comprises a plurality of bits, the non-station identification masked field comprises at least one bit, and the method de-masks the bits in the station identification masked field by a station identification of the wireless apparatus and de-masks the at least one selected bit in the data portion and the at least one bit in the non-station identification masked field by an extended-station identification of the wireless apparatus. 
     
     
       4. A wireless apparatus for a network system, the network system comprising a base station and the wireless apparatus, the wireless apparatus comprising:
 a receiving unit for receiving a packet from the base station, wherein the packet comprises a data portion and a cyclic redundancy check portion; and 
 a processing unit, electronically connected to the receiving unit and is configured for generating a de-masked packet by de-masking the cyclic redundancy check portion and at least one selected bit of the data portion by a plurality of predetermined bits, determining that the de-masked packet passes a cyclic redundancy check, and then accepting the packet after the determination; 
 wherein the data portion has at least one selected position for placing the at least one selected bit, the at least one selected position corresponds to a plurality of possible bit streams, a first vector space is formed by a plurality of redundancies by applying a cyclic redundancy check polynomial to each of the possible bit streams, a second vector space is further formed by a plurality of redundancies by applying the CRC polynomial to each of all possible bit streams in the CRC portion, and the first vector space and the second vector space do not overlap. 
 
     
     
       5. The wireless apparatus of  claim 4 , wherein the cyclic redundancy check portion is defined with a station identification masked field, the station identification masked field comprises a plurality of bits, the processing unit de-masks the bits in the station identification masked field by a station identification of the wireless apparatus, and the processing unit de-masks the at least one selected bit in the data portion by an extended-station identification of the wireless apparatus. 
     
     
       6. The wireless apparatus of  claim 4 , wherein the cyclic redundancy check portion is defined with a station identification masked field and a non-station identification masked field, the station identification masked field comprises a plurality of bits, the non-station identification masked field comprises at least one bit, and the processing unit de-masks the bits in the station identification masked field by a station identification of the wireless apparatus and de-masks the at least one selected bit in the data portion and the at least one bit in the non-station identification masked field by an extended-station identification of the wireless apparatus.